There are known household heating appliances in the prior art that include pilot burners with oxygen depletion sensors. The level of oxygen in a typical ventilated room is generally around 21%, which allows the combustion of a combustible fluid to take place correctly. Problems arise when the level of oxygen falls below 18%, a situation that may occur in non-ventilated household heating appliances and which leads to poor combustion of the combustible fluid, carbon monoxide thus being generated and causing a corresponding danger to the user. To prevent the problem, pilot burners include oxygen depletion sensors that block the passage of combustible fluid to the burners when the level of oxygen detected falls below 18%.
Known single gas pilot burners with oxygen depletion sensors generally comprise a safety thermocouple that generates an electrical current when heated by a pilot flame, the electrical current acting on a control valve to keep it open and, therefore, the passage of combustible fluid to the burners of a heating appliance, a spark generator that causes the ignition of the combustible fluid, an injector that comprises a mixing chamber where air is mixed with the combustible fluid, and a nozzle through which the injector supplies the pilot flame that heats the safety thermocouple, the safety thermocouple, the spark generator and the injector typically being fixed on a support to the interior of the heating appliance.
There are also known dual gas heating appliances in the prior art (i.e., heating appliances that may be supplied by two different combustible fluids), the combustible fluids preferably being natural and propane gas, and which include a pilot burner with oxygen depletion sensor for each combustible fluid, with the result that two each of most of the necessary components are required
United States patent application published as US2007/0266765 A1 discloses a dual heating appliance that incorporates a single pilot burner for both combustible fluids, the pilot burner comprising a safety thermocouple, a spark generator, a first injector that is supplied with a first combustible fluid, and a second injector that is supplied with a second combustible fluid, the safety thermocouple, the spark generator and the first and second injectors being supported on a single support. The first injector and the second injector are disposed at an angle in relation to the safety thermocouple and facing each other, with the result that a first pilot flame supplied by the first injector heats one face of the safety thermocouple, while a second pilot flame supplied by the second injector heats the other face of the safety thermocouple.